pointers

问题 So I want to give an example: int *pi; // pi is a pointer that points to an integer const int *cpi; // cpi is a pointer that points to a constant integer char *pc; // pc is a pointer to a char How can I read these: char **x; //x is a pointer to a char pointer? char *y[]; char **z[]; Thanks. 回答1: cdecl.org is often linked to such questions. No doubt that it make easier to decipher any complex declaration, but at the same time it just provide an abstracted information. Being a C or C++

问题 I don't know why the below happens, and I can't find source code relative. Can anybody explain to me? var s, ss struct{} // two empty structs arr1 := [6]*struct{}{&s} // array with empty struct pointer arr2 := [6]*struct{}{&ss} // array with empty struct pointer fmt.Println(&s == &ss, arr1 == arr2) // false, true var l, ll struct{A int}{} arr3 := [6]*struct{A int}{&l} // array with empty struct pointer arr4 := [6]*struct{A int}{&ll} // array with empty struct pointer fmt.Println(&l == &ll,

问题 I don't know why the below happens, and I can't find source code relative. Can anybody explain to me? var s, ss struct{} // two empty structs arr1 := [6]*struct{}{&s} // array with empty struct pointer arr2 := [6]*struct{}{&ss} // array with empty struct pointer fmt.Println(&s == &ss, arr1 == arr2) // false, true var l, ll struct{A int}{} arr3 := [6]*struct{A int}{&l} // array with empty struct pointer arr4 := [6]*struct{A int}{&ll} // array with empty struct pointer fmt.Println(&l == &ll,

问题 I don't know why the below happens, and I can't find source code relative. Can anybody explain to me? var s, ss struct{} // two empty structs arr1 := [6]*struct{}{&s} // array with empty struct pointer arr2 := [6]*struct{}{&ss} // array with empty struct pointer fmt.Println(&s == &ss, arr1 == arr2) // false, true var l, ll struct{A int}{} arr3 := [6]*struct{A int}{&l} // array with empty struct pointer arr4 := [6]*struct{A int}{&ll} // array with empty struct pointer fmt.Println(&l == &ll,

问题 To convert a map whose values are strings into one whose values are points to string, I need to copy the string first. If I do not, all the values are the same, potentially wrong value. Why is this? I am not taking the address of a string literal here. func mapConvert (m map[string]string) map[string]*string { ret := make(map[string]*string) for k, v := range m { v2 := v[:] ret[k] = &v2 // With the following instead of the last 2 lines, // the returned map have the same, sometimes wrong value

问题 Before the actual question, small prelude. I don't care about security, I do care about performance. I KNOW this is not proper and I know it's very hacky, however this is quite fast. vector<float> result = move(*((vector<float>*)&vertices)); That code is abusing C style casts and pointers to force the compiler to interpret the left hand side array vertices which is a vector of a compact type where all the fields are float as an array of floats. i.e struct vertex { float x; float y; float z; }

问题 // I need to download data from the (json-format) file net_f: std::ifstream net_f("filename", std::ios::in | std::ios::binary); // to a square int array *net of size n: int n; int * net; load_net(net_f, &n, net); // The size is initially unknown, so I want to do it in the procedure: void load_net(std::ifstream& f, int *n, int *net) { int size; // # of rows (or columns, it's square) in the array int net_size; // the array size in bytes /* some code here to process data from file */ //

问题 I am writing a code to make a linked list. one of the function I wrote in order to make a linked list easier in the main function was[node is the name of a struct conatains a.data b.pointer name next) : node& create_node(int value) { node newitem; newitem.data=value; newitem.next=NULL; return (newitem); }; When I write the function like this everything is ok but I want to write the function header as : node * create_node(int value) But when I write it that way and I write return *newitem; I

问题 I want to pass a structure pointer to a function that will dynamically create a array of structures at the location pointed to by the structure pointer that was passed. I am able to create and fill the array of structure successfully but when trying to print the data in the calling function using the pointer that was passed gives me a garbage values. Please help me know why my structure pointer is pointing to garbage and how can I access my data correctly. The following is just some example

问题 I'm referring Parent class from Child class; instead of simply do, for example: Public Property Set Parent(obj As ClassProperties) Set this.ParentColl = obj End Property I rather prefer to avoid references to and from getting entangled and 'out of memory' error when I loop through and create instances of the class so I use this that is based on that. It functions as a charm in 32 bits but at 64 bits I'm getting Runtime error '53' File not found: kernel. In a module: #If VBA7 Then Private